Admin

I can not access the site administration,

in the database but the user is displayed in the search on the site where trying to display the profile I have this message "NOT AVAILABLE FOR VIEW PROFILE"

all other users are displayed with their file sent like those sent by the Administrator in news, but the Administrator account exists in the database but not in the site

That sucks. Try these:

• Check your database to make sure that your Admin account is set to Active.
• Check your database to make sure that your Admin account is set to the Admin role (3).
• Did you make any changes to the site recently? If you edited any files, you might have accidentally tripped something. Try uploading unedited versions of any files you recently uploaded (back up your site first and you can "back up" edited files by simply renaming them from file-name.php to file-name.php.old, obviously substituting your actual file names).
• Clear the cache (always always clear the cache).
• Add a new Admin id to your site. (The easiest way to do this is with Deano's Tools, but since you can't access the Admin page you can't use Deano's Tools. Bummer.)  Register as a new user on your site. Go into your database and set the new username to be an Admin by changing their role from 1 to 3. Log in as the new user and you should be able to access the Admin pages.
• Or your admin pages might be screwy, you can reupload a fresh copy of the admin section of your site, clear the cache and try again.

Good luck.